Die head



Jail. 25,1921.

C. W. BETTCHER DIE HEAD Filed Aug. 21, 1924 .2 Sheets-Sheet l INVENTOR. (Saul. m;- BY 7 ATTORNEY.

Jan. 25, 1927. a BETTCHER DIE HEA'D Filed Aug. 21. 1924 2 Sheets-Sheet E INVENTOR. @M M: 3% BY ,ATTORNEY 4 Patented Jan. 25, 1927.

UNITED STATES PATENT OFFICE.

CARL W. BETTCHER, OF NEW HAVEN, CONNECTICUT, ASSIGNOR TO THE EASTERN MA- CHINE SCREW CORPORATION, OF NEW HAVEN, CONNECTICUT.

DIE HEAD.

Application filed August 21, 1924. Serial No. 733,271.

My invention relates to an improvement in die heads adapted for use in connection with automatic machines, wherein the die head spindle rotates while the stock, on

which the thread is cut, remains stationary.

My improvement consists in providing means for a more accurate adjustment for the length of thread to be cut that is absolutcly positive in its action.

Referring to the accompanying drawings, wherein the same characters of reference indicate like parts throughout the several views:

Figure 1 represents a side elevation of a die head and its superimposed tripping shell showing the die head temporarily locked therein preparatory to thread cutting, also a broken view of the die head shank;

Figure 2 is a front elevation of the d1e head and trip shell showing the threading dies or chasers advanced for cutting threads;

Figure 3 is a side elevation of the die head and broken view of its shank, tripping shell showing the position of the die head when released;

Figure 4 is a front elevation of the d1e head with the threading dies withdrawn;

Figure 5 is a side elevation of the die head and broken view of its shank;

Figure 6 is a detail side elevation of that part of the die head carrying the threading dies and broken view of its shank;

Figure 7 is a detail front elevation of that part of the die head carrying the trip lever and die actuating cam studs;

Figure 8 is a detail front elevation of the tripping shell adapted to ,be operatively mounted on the die head;

Figure 9is a central sectional view of the tripping shell on line 9-9 of Figure 8, and broken view of the die head;

Figure 10 is a broken view partly in section of the die head on line 10-10 of Fig ure 4, and

Figure 11 is a reduced view of the die head and broken view of its actuating mechanism.

The die head proper comprises the threading die carrying head 1 and the recessed.

shell 2. A brief description of their well known construction may be necessary before setting forth my improvement in connection therewith.

The head 1 is provided with the radial slots 3, Figure 2, in which are located the radially operating threading dies 4. 5 is a plate secured to the head 1 by the screws 6, and 7,. Figure 4, are the threaded holes in the head for said screws. Sisalocking bolt longitudinally adjusted in said head bythe screw 9, Which screw is held in place by the set screw 10. 11 is a shank integral with said head.

The recessed shell 2, Figure 7 has the cen tral opening 12 through which the shank 11 of the head 1 has a free longitudinal movement. 13 is a hole in the base of said shell in line with the locking bolt 8 of the head 1, and 14 is a plate secured to said base. The shell 2 is operatively connected to the head 1 by the screw 15 whose inner end 15 enters the elongated-recess 16, Figure 6, of the shank 11. i

17 is a trip lever pivotally mounted on the pin 18 whose tail piece 17 a is adapted to automatically engage the indent 8 Figure 6, of the locking bolt 8 through the medium of the pin 19, Figure 7 and its actuating spring 20. 21 are studs secured to the baseof the shell 2 and project therefrom and pass freely through holes in the head 1. These studs 30 have the well known cam faces 21 adapted to operate in the cam grooves 22, Figure 10, formed in the face of the threading dies to advance and retreat the same.

Holes 23, Figure 7, are formed in the shell 2 adapted to receive springs located in the head 1 and force back said shell and open the dies when the lever 17 is tripped. One of said springs 24, is shown in Figures 5 and 6. r

The improved feature consists in associating the outer tripping shell 25 with a die head of the character above set forth. The die head proper is operatively located within this outer shell and has a certain amount 95 of independent movement therein. 26 and 27 are screws passing through the elongated slots 28 and 29 of the outer shell 25, Figures 1 and 9, and are secured to the inner shell 2 of the die head.

The spring 30 and the loose pin 31, located between the cap screw 32 and screw 26, Figure 1, are duplicates of a similar construction in connection with the screw 27 and cap screw 33, Figure 2, located on the opposite sides of the shell 25.

The continuous beveled recess 34, Figure 9, is formed on the interior of the outer shell 25 for the reception of the trip lever 17. The opening 35, Figure 8, in the front of this shell opens into the recess 34 for the free insertion of the trip lever when the die head is inserted in the outer shell. When the die head has been seated in said shell, it is rotated therein to carry the trip lever out of alignment with the opening 35 and opposite the beveled portion of the recess 34, as shown in Figure 9.

36, Figure 11, is a spindle attached to the shank 11 and adapted to be connected with various types of automatic machines or drill presses, not shown, and has both a rotative and a longitudinally reciprocative movement. 37 is a spool integral with the outer shell to receive the fork 38 adapted to have a sliding movement on the rod 39.

In Figure 11 the different members are in position for cutting a thread on the stationary rod 40. The rotatable die head and its outer shell 25 is advanced by the spindle 36 to engage the dies with said rod. The side springs engaging screws 26, 27, serve to hold the shell 25 back so that it will travel in unison with the die head until said shell is halted by the contact of the fork 38 with the collar 41-1 on the rod 39. The shell 25 thus halted, the die head will continue to advance until the trip lever 17, Figure 9, is brought against the inclined face 34 of the recess 3% and tripped.

This continued forward movement of the die head will compress said side springs, and their stored up tension will force the shell 25 to its normal position on the die head, and the springs 24 will also force the shell 2 back to open the dies the instant that the lever 17 is tripped. The instant the tripping takes place the spindle 36 will retreat and withdraw the die head and shell 25 until the latter is halted when the fork 38 brings up against the collar 42. lVith the backward movement of the shell 25, thus halted, the retreating spindle 36 will draw the head 1 into locking engagement again with the trip lever 17 of the shell 2 in readiness for further thread cutting.

It has heretofore been customary to have the trip lever exposed outside of the cam stud carrying member and tripped by contact with a stationary pin lying in the path of the advancing rotatable die head. If the trip lever ust misses the pin, it has to make one more complete rotation before tripping. This method of tripping is very apt to 02;- tend the travel of the die head beyond the limit originally intended, and thus cause more or less trouble in cutting short threaded screws, where the letting go of the threading dies at a certain predetermined point must be positively assured. This positive tripping feature is fully provided for in the present instruction, whereby the tripping means is located entirely within the outer shell and is absolutely certain to function at a predetern'iined point and cause the dies to open.

Forming the recess 3% around the inner circumference of the outer shell, permits the ready location of the trip lever at any point within this recess, except opposite the opening for assured action.

T he exact means for advancing and retreating the die head, or temporarily halting the outer tripping shell at certain points, pertains to machine construction with which the die head is to be associated, and any suitable means for this purpose could be employed.

While I show a die head of a certain con struction with my improved tripping shell installed thereon, it will be distinctly understood that it is applicable to any and all die heads equipped with means for releasing the threading dies.

Having thus-described my invention what I claim and desire to secure by Letters Patent is 1. In combination with die head mechanism comprising a member carrying radially operating threading dies, a member slidably mounted thereon and carrying means for opening and closing the dies, and also carrying a trip lever for locking the closed dies and unlockingthe same, of a tripping shell embracing the trip lever having an internal circmnferential recess for the reception of the trip lever and for tripping the same, and spring means for tensioning said trip lever -arrying member with respect to said shell so that it will have an independent forward movement after the tripping shell is halted.

2. A construction as in claim '1, in which the trip lever has a freedom of movement in the recess until tripped by the indcpcmlcnt movement of the tripping shell.

3. A construction as in claim 1, in which the spring tension stored up in the tripping shell will return the tripping shell to its normal position when the die head is restored to its initial position.

1. A construction as in claim 1, in which one face of the tripping shell is provided with an opening leading into the internal recess for the entrance of the trip lever in assembly of the structure.

5. A die head having radially operating for operating the trip lever, rotating and threading dies, a shell freely mounted therelongitudinally reciprocating means operaon carrying means for actuating the dies to tively connected to the die head, and means 10 open and close position, and a trip lever for for temporarily halting the longitudinal 5 locking the closed dies and releasing the movement of the tripping shell.

same, a tripping shell embracing the trip In testimony WhereofI am); my signature.

lever and having an interior tripping recess CARL 4V. BETTCHER. 

